High current Switching

Discussion in 'The Projects Forum' started by BiggestMad, Oct 30, 2012.

  1. BiggestMad

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    Dear All,
    Following is my project brief:
    1.MCU controlled switching is used for High current (250mA).
    2.Load 1 to 8 will be switching ON/OFF in chain-sequence one by one.
    3.Load 1 will be ON for 200uS while rest of the loads will be OFF. then Load 2 will be ON for 200uS while rest of the loads will be OFF and so on...
    4. Schematic is in attachments

    [​IMG]

    Requirement..
    A. Instead of the switches shown in schematic, a chip is required to perform high current, high speed switching (5.1KHz).
    B. What kind of chip/chip array is best suitable for this time of applications?
    Darling array, MOSFET etc..??
    C. Can following ICs be used for this application?
    ULN2803
    DMP2240UDM
    :confused:

    Please advice...
     
  2. panic mode

    Senior Member

    Oct 10, 2011
    1,320
    304
    use ULN2803A.

    if you are not multiplexing, connect one side of loads to it's outputs, the other side to +5V.
     
  3. DickCappels

    Moderator

    Aug 21, 2008
    2,656
    632
    Thanks for telling us.
    Do you have a question?
     
  4. BiggestMad

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    It has to be a current source driver as sink driver is attached at the end.
    Thats why I was wondering if UDN2981A can be used or not as its a source driver? Datasheet suggests it need 15 to 50V as Vs (supply voltage). Can this be used with 5V supply voltage?
     
  5. BiggestMad

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    here are the questions (sorry if i didn't make myself clear);

    B. What kind of chip/chip array is best suitable for this time of applications?
    Darling array, MOSFET etc..??
    C. Can following ICs be used for this application?
    UDN2981A
    DMP2240UDM


    Please advice...
     
  6. panic mode

    Senior Member

    Oct 10, 2011
    1,320
    304
    UDN chips like UDN2981A, UDN2982A are high side switches. the main issue is that they are not open collector devices so Vce drop of any output is some 2V. so pair of transistor (NPN/PNP and couple of resistors) per channel is your best bet
     
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